Colonization of the upper jejunum by enteropathogenic and enterotoxigenic Escherichia coli in paediatric diarrhoea

Aspirated fluid from the upper jejunum was obtained by intubation of 27 children with diarrhoea and 7 control children without diarrhoea. The aspirated jejunal fluid was analysed for total counts of viable aerobic and anaerobic microorganisms. Gram-negative aerobic bacteria were typed biochemically and analysed for the production of heat-labile and heat-stable enterotoxin. Enteropathogenic Escherichia coli (EPEC) strains of serogroups 0111, 055 and 0127 were detected in the stools of nine patients and the respective strains concomitantly in the upper jejunum (10(3)-10(8) bact/ml) in 7 patients with diarrhoea. In 6 patients from whom isolates of enterotoxigenic E. coli (ETEC) were obtained, there were high total viable counts of non-enterotoxigenic bacteria in the upper jejunum and ETEC were recovered from this location in 3 cases. Enterotoxigenic Klebsiella was recovered from faeces but not from upper jejunum in one case. Compared to the controls, the total number of bacteria in the upper jejunum were 100-1000 times higher in patients with enteropathogenic E. coli (EPEC) or enterotoxigenic E. coli (ETEC). In another 11 cases with diarrhoea caused by Shigella, rotavirus or of unknown aetiology, the total viable counts of bacteria were similar to those of the controls. Five patients with severe EPEC diarrhoea received antibodies for 5 days. The patients improved clinically, and the EPEC strain had disappeared from the upper jejunum when they were reexamined. In conclusion, in EPEC diarrhoea a colonization of the upper jejunum by the causative organism seemed to take place, while in ETEC diarrhoea, there appeared to be a nonspecific contamination by enteric bacteria.     

COLONIZATION OF THE UPPER JEJUNUM BY ENTEROPATHOGENIC AND ENTEROTOXIGENIC ESCHERICHIA COLI IN PAEDIATRIC DIARRHOEA

ABSTRACT. Aspirated fluid from the upper jejunum was obtained by intubation of 27 children with diarrhoea and 7 control children without diarrhoea. The aspirated jejunal fluid was analysed for total counts of viable aerobic and anaerobic microorganisms. Gram-negative aerobic bacteria were typed biochemically and analysed for the production of heat-labile and heat-stable enterotoxins. Enteropathogenic Escherichia coli (EPEC) strains of serogroups 0111, 055 and 0127 were detected in the stools of nine patients and the respective strains concomitantly in the uper jejunum (10³-10⁸ bact/ml) in 7 patients with diarrhoea. In 6 patients from whom isolates of enterotoxigenic E. coli (ETEC) were obtained, there were high total viable counts of non-enterotoxigenic bacteria in the upper jejunum and ETEC were recovered from this location in 3 cases. Enterotoxigenic Klebsiella was recovered from faeces but not from upper jejunum in one case. Compared to the controls, the total number of bacteria in the upper jejunum were 100-1000 tunes higher in patients with enteropathogenic E. coli (EPEC) or enterotoxigenic E. coli (ETEC). In another 11 cases with diarrhoea caused by Shigella , rotavirus or of unknown aetiology, the total viable counts of bacteria were similar to those of the controls. Five patients with severe EPEC diarrhoea received antibiotics for 5 days. The patients improved clinically, and the EPEC strain had disappeared from the upper jejunum when they were reexamined. In conclusion, in EPEC diarrhoea a colonization of the upper jejunum by the causative organism seemed to take place, while in ETEC diarrhoea, there appeared to be a nonspecific contamination by enteric bacteria.     

Colostrum from healthy Brazilian women inhibits adhesion and contains IgA antibodies reactive with Shiga toxin-producing <Emphasis Type="Italic"> Escherichia coli</Emphasis>

Although Shiga toxin-producing Escherichia coli (STEC) has been isolated in Brazil, severe manifestations of the infection, such as haemorrhagic colitis and haemolytic-uraemic syndrome, are extremely rare in our population. Enteropathogenic Escherichia coli (EPEC) is the main aetiological agent of acute infantile diarrhoea in Brazil. There are many similarities between STEC and EPEC, such as the ability to produce attaching and effacing (A/E) lesions and some virulence-associated factors. Our aim was to investigate the presence of anti-STEC antibodies in healthy people living in an EPEC endemic area. Colostrum samples collected from 51 women living in low socio-economic conditions were analysed. Two STEC strains: O111:H- (Stx1) and O157:H7 (Stx2), and one EPEC strain (O111:H-) were used in the bacterial adhesion assays to HEp-2 cells, in the Stx1 and Stx2 cytotoxicity assays on Vero cells, in immunoblotting and in ELISA assays. All the samples strongly inhibited the adhesion of the three strains and contained SIgA antibodies reactive with antigens of EPEC O111:H-, STEC O111:H- and STEC O157:H7, mainly STEC and EPEC 94 kDa adhesin intimin. High titres of anti-LPS O111 antibodies were found in many samples. Nevertheless, the cytotoxic effect of both Stx1 and Stx2 on Vero cells was not neutralised by any sample. Conclusion: Our results suggest that Brazilian people may be exposed to Shiga toxin-producing Escherichia coli more frequently than previously thought or alternatively there may be a cross reactive immunity between enteropathogenic Escherichia coli and Shiga toxin-producing Escherichia coli.     

Cluster of hemolytic-uremic syndrome caused by Shiga toxin-producing Escherichia coli O26:H11

BACKGROUND: The epidemiology and clinical characteristics of the hemolytic-uremic syndrome (HUS) caused by Escherichia coli O157:H7 are well-known, but HUS attributable to non-O157:H7 Shiga toxin (Stx)-producing E. coli (STEC) are less thoroughly described. Here we report a cluster of HUS cases caused by STEC O26:H11 the most common non-O157:H7 STEC isolated from sporadic cases of HUS in Europe. METHODS: Three children between 13 and 17 months of age, living in the same small town, developed HUS within an interval of 5 days. We present clinical and microbiologic data on the patients and their infecting isolates. RESULTS: The clinical course ranged from mild uncomplicated HUS to severe HUS complicated by multiorgan involvement. Microbiologic investigation demonstrated STEC of serotype O26:H11 in stools of all the patients. The phenotypic and molecular characterization of the STEC O26:H11 isolates demonstrated that these strains were identical and, unusual for STEC O26, they harbored the stx2 but not the stx1 gene. None of the patients had evidence of STEC O157:H7 infection either by culture or by E. coli O157 serology. The source of the STEC O26:H11 infection was undetermined. CONCLUSIONS: Our results demonstrate that diagnostic procedures based on the detection of stx genes and/or Stx production and subsequent subtyping of the isolates using molecular methods are necessary to identify such outbreaks caused by non-O157:H7 STEC.     

Shiga toxin-producing Escherichia coli in children with diarrhea: a prospective point-of-care study

OBJECTIVE: To conduct a prospective cohort study to determine the frequency and characteristics of Shiga toxin (Stx)-producing Escherichia coli (STEC) infections in children with diarrhea attending an emergency department and a private clinic in Seattle, Washington. METHODS: Between November 1998 and October 2001, 1851 stools were processed for STEC by sorbitol-MacConkey (SMAC) agar screening and a commercial Stx enzyme immunoassay (EIA). RESULTS: STEC belonging to serotypes O157:H7 (n = 28), O103:H2 (n = 4), O118:H16 (n = 2), O26:H11, O111:nonmotile, O111:H8, O121:H19, and O rough:H11 (n = 1 each) were recovered from 39 (2.1%) stools. EIA and SMAC agar detected 89% and 100% of the patients with E coli O157:H7, respectively. E coli O157:H7-infected patients had significantly higher frequencies of bloody stools, fecal leukocytes, and abdominal tenderness and shorter symptom duration. Hemolytic uremic syndrome developed in 5 (18%) and none of the children infected with E coli O157:H7 and non-O157:H7 STEC, respectively (P =.30). CONCLUSIONS: E coli O157:H7 is the predominant STEC in this population. Children infected with E coli O157:H7 have clinical presentations different from those whose stools contain non-O157:H7 STEC. Culture and Stx detection are needed to optimally detect STEC of all serotypes in stools. SMAC agar screening should not be replaced by EIA.     

Nationwide study of haemolytic uraemic syndrome: clinical, microbiological, and epidemiological features.

AIMS: To establish the incidence and aetiology of haemolytic uraemic syndrome (HUS) in Australia and compare clinical and microbial characteristics of sporadic and outbreak cases. METHODS: National active surveillance through the Australian Paediatric Surveillance Unit with monthly case notification from paediatricians, July 1994 to June 1998. Children under 15 years presenting with microangiopathic haemolytic anaemia, thrombocytopenia, and acute renal impairment were identified. RESULTS: Ninety eight cases were identified (incidence 0.64 per 10(5) children <15 years/annum and 1.35 per 10(5) children <5 years/annum). Eighty four were associated with diarrhoea (64 sporadic, 20 constituting an outbreak) and 14 were atypical. Shiga toxin producing Escherichia coli (STEC) O111:H- was the most common isolate in sporadic HUS and caused the outbreak. However O111:H- isolates from outbreak and sporadic cases differed in phage type and subtyping by DNA electrophoresis. STEC isolates from sporadic cases included O26:H-, O113:H21, O130:H11, OR:H9, O157:H-, ONT:H7, and ONT:H-. STEC O157:H7 was not isolated from any case. Only O111:H- isolates produced both Shiga toxins 1 and 2 and possessed genes encoding E coli attaching and effacing gene (intimin) and enterohemolysin. Outbreak cases had worse gastrointestinal and renal disease at presentation and more extrarenal complications. CONCLUSIONS: Linking national surveillance with a specialised laboratory service allowed estimation of HUS incidence and provided information on its aetiology. In contrast to North America, Japan, and the British Isles, STEC O157:H7 is rare in Australia; however, non-O157:H7 STEC cause severe disease including outbreaks. Disease severity in outbreak cases may relate to yet unidentified virulence factors of the O111:H- strain isolated.     

Enteropathogenic Escherichia coli (EPEC) and enterotoxigenic (ETEC) related diarrhoeal disease in a neonatal unit

In an outbreak of summer diarrhoea in the neonatal unit, King Edward VIII Hospital, Durban, 25 (69%) of the 36 infants had organisms demonstrated in their stools. Four (11%) had EPEC alone, six (17%) ETEC alone, six (17%) EPEC plus rotavirus and nine (25%) all three organisms. Eleven (30%) infants had no organisms in their stools. Rotavirus alone was not present in any of the stools. Seven infants had septicaemia. The overall mortality was 22% and 62.5% of the deaths occurred in low birthweight infants. In a study of 41 infants without diarrhoea during the following winter and summer periods 55% of winter, 43% of summer controls, and four of 12 (33%) mothers had rotavirus. Only two (4.8%) of 41 infants had E. coli (EPEC). The findings suggest that E. coli (EPEC strain 044/K74[c], and ETEC) was the major cause of the outbreak and it was associated with a high mortality.     

Quantitation and properties of fecal and upper small intestinal aerobic microflora in infants and young children with persistent diarrhea

The duodenal juice and fecal aerobic microflora was investigated in 54 patients with persistent diarrhea (age less than or equal to 2 years). The duodenal aspirates yielded increased aerobic bacteria (greater than 10(5) organisms/ml) in 28 (51.9%) of the patients. Established enteric pathogens were isolated from the duodenal aspirates of 12 (22.2%) of the 54 patients, viz., enteroadherent Escherichia coli (EAEC) (5), enterotoxigenic E. coli (ETEC) (3), enteropathogenic E. coli (EPEC) (1), nontyphoidal Salmonella (1), and Giardia lamblia (2). The total aerobic bacterial count was greater than 10(5) in all 12 patients positive for specific pathogens apart from one case in whom E. coli showing diffuse adherence to HEp-2 cells were identified. Among the remaining 42 specific pathogen-negative patients, 19 (45.2%) also had greater than 10(5) aerobic organisms/ml in the small bowel. Eight strains of Klebsiella from four of the patients were negative for enterotoxin production in a rabbit ileal loop assay and for adherence to HEp-2 cells. In contrast, 28/54 (51.9%) of the same patients had known enteric pathogens in their stools, viz., nontyphoidal Salmonella (8 or 14.8%), Shigella (2 or 3.7%), Campylobacter (1 or 1.9%), ETEC (4 or 7.4%), EPEC (2 or 3.7%), EAEC (7 or 13.0%), and G. lamblia and Entameba histolytica (3 or 5.6%). Further search for potential virulence factors among aerobic bacteria colonizing the upper small intestine in persistent diarrhea is warranted.     

Aetiological factors of infantile diarrhoea: a community-based study

A community-based study was undertaken to compare the organisms responsible for diarrhoea in children living in formal housing with indoor water supply and sanitation with those from a deprived environment. The role of "home remedies" was also assessed. Among 373 children with diarrhoea, rotavirus was detected in 15% (in 371 symptom-free controls, 9%), and proved to be the single most common causative agent. Bacterial pathogens were found in 20% of patients, with enteropathogenic Escherichia coli (EPEC) being isolated most frequently (9%; controls 3%), followed by Shigella species (4%; controls 1%), Campylobacter jejuni (4%; controls 1%), Salmonella species (2%; controls 1%) and enterotoxigenic E. coli (ETEC) (2%; controls 1%). Giardia lamblia and cryptosporidium were detected in 6% (controls 6%) and 3% (controls 1%) of patients, respectively; 7% (controls 1%) harboured more than one enteropathogen and no pathogens were detected in 58% (controls 78%). The vast majority (greater than 90%) of both patients and controls received some form of "home remedy" which included disinfectants and traditional herbs. The findings of this study therefore confirm the extremely complex nature of diarrhoea in developing communities and indicate that environmental factors are compounded by other issues.     

Saliva IgM and IgA are a sensitive indicator of the humoral immune response to Escherichia coli O157 lipopolysaccharide in children with enteropathic hemolytic uremic syndrome

Saliva antibodies to Escherichia coli O157 were investigated as markers of the immune response in children with enteropathic hemolytic uremic syndrome (HUS). Paired serum and saliva samples were collected from 22 children with HUS during acute disease and convalescence and were tested for E. coli O157 lipopolysaccharide (LPS)-specific IgM and IgA antibodies by ELISA. Serum and saliva samples from 44 age-matched controls were used to establish the cut-off values. Elevated levels of IgM and/or IgA antibodies to O157 LPS were detected in saliva of 13/13 HUS patients with Shiga toxin-producing E. coli (STEC) O157 in stool culture and from 4 of 5 HUS patients in whom STEC were not detected. These results closely mirrored the results obtained with paired serum samples. In contrast, saliva and serum samples from four children with STEC isolates belonging to O-groups O26, O145 (n = 2), and O165 lacked detectable O157 LPS-specific antibodies. The specificity of the ELISA was confirmed by western blotting. In STEC O157 culture-confirmed cases, the sensitivity of the ELISA was 92% for saliva IgM and IgA, based on the first available sample, and 100% and 92%, respectively, when subsequent samples were included. The specificity was 98% for IgM and 100% for IgA. Children with E. coli O157 HUS demonstrate a brisk, easily detectable immune response as reflected by the presence of specific antibodies in their saliva. Saliva-based immunoassays offer a reliable, noninvasive method for the diagnosis of E. coli O157 infection in patients with enteropathic HUS.     

Prevalence of verocytotoxigenic Escherichia coli serotype O157:H7 in children with diarrhoea attending a Sydney hospital

Abstract Verotoxin producing Escherichia coli, in particular serotype O157:H7, have been implicated as an important cause of acute gastroenteritis in children. This study was undertaken to determine if E. coli O157:H7 is an important cause of acute gastroenteritis in children in metropolitan Sydney. During the period from October 1990 to September 1991, stools from patients presenting with acute diarrhoea to The Children's Hospital, Camperdown, were examined for the presence of common bacterial pathogens. In addition, stools were grown on sorbitol McConkey agar and sorbitol non-fermenting organisms were serotyped with O157 antiserum by slide agglutination. The isolates were then tested with H7 antisera and investigated for the production of verocytotoxin and other pathogenic markers including plasmid-associated EHEC adhesin and chromosomally encoded attachment-effacement gene. Only two strains (isolated from two different patients, 0.1% of specimens tested) were agglutinated by O157 antiserum and both were non-motile (H^-). However, both strains produced verotoxin and expressed other virulence markers, suggesting that they were responsible for the diarrhoea. Both patients experienced mild, self limited gastroenteritis. We conclude that E. coli O157:H7 is an uncommon cause of acute gastroenteritis in Sydney children presenting to a children's hospital.     

Vertical transmission of enteric pathogens at birth

To determine how frequently mothers infect their infants with enteric pathogens at birth, stools were collected from 75 Thai mothers immediately before delivery and from their infants 24-48 h later. Enteropathogenic Escherichia coli (EPEC) were isolated from 25 of the 75 mothers just prior to delivery (32%), enteroviruses from six (8%), enterotoxigenic E. coli from five (7%), and shigella, salmonella and Vibrio parahaemolyticus each from one (1%). EPEC serotype 0128:K67 was isolated from one mother and from her infant, neither of whom had diarrhoea. Cultures from the other 74 mother-infant pairs did not detect identical enteric pathogens. Eighteen infants, nine of whose mothers submitted stools prior to delivery, developed diarrhoea within 5 days of birth. Five infants were infected with ETEC (28%), three with EPEC serotype 020a020cK61 (17%), one with Campylobacter jejuni (6%), and one with rotavirus (6%). None of these enteropathogens was found in 66 infants without diarrhoea. ECHO viruses of two different serotypes were isolated from two of 18 newborns with diarrhoea and unidentified enteroviruses from three of 66 without diarrhoea. Mothers and nurses are frequently infected with enteric pathogens in Thailand, but transmission to newborns at birth appears to be uncommon.     

Nationwide study of haemolytic uraemic syndrome: clinical, microbiological, and epidemiological features

AIMS—To establish the incidence and aetiology of haemolytic uraemic syndrome (HUS) in Australia and compare clinical and microbial characteristics of sporadic and outbreak cases.
METHODS—National active surveillance through the Australian Paediatric Surveillance Unit with monthly case notification from paediatricians, July 1994 to June 1998. Children under 15 years presenting with microangiopathic haemolytic anaemia, thrombocytopenia, and acute renal impairment were identified.
RESULTS—Ninety eight cases were identified (incidence 0.64 per 10⁵ children <15 years/annum and 1.35 per 10⁵ children <5 years/annum). Eighty four were associated with diarrhoea (64 sporadic, 20 constituting an outbreak) and 14 were atypical. Shiga toxin producing Escherichia coli (STEC) O111:H− was the most common isolate in sporadic HUS and caused the outbreak. However O111:H− isolates from outbreak and sporadic cases differed in phage type and subtyping by DNA electrophoresis. STEC isolates from sporadic cases included O26:H−, O113:H21, O130:H11, OR:H9, O157:H−, ONT:H7, and ONT:H−. STEC O157:H7 was not isolated from any case. Only O111:H− isolates produced both Shiga toxins 1 and 2 and possessed genes encoding E coli attaching and effacing gene (intimin) and enterohemolysin. Outbreak cases had worse gastrointestinal and renal disease at presentation and more extrarenal complications.
CONCLUSIONS—Linking national surveillance with a specialised laboratory service allowed estimation of HUS incidence and provided information on its aetiology. In contrast to North America, Japan, and the British Isles, STEC O157:H7 is rare in Australia; however, non-O157:H7 STEC cause severe disease including outbreaks. Disease severity in outbreak cases may relate to yet unidentified virulence factors of the O111:H− strain isolated.

     

Aetiology of diarrhoea in adequately nourished young African children in Durban, South Africa

Two inter-related hospital-based studies on the causes of diarrhoea in African children who were not overtly malnourished, were performed over a period of two years in Durban, South Africa. The first study involved 126 inpatients selected for previously untreated diarrhoea of less than 96 h duration. On examination and culture of the stools of these children bacteria were identified in 60%, rotavirus in 20% and parasites in 4%. No pathogens were identified in 33%. The bacteria most frequently encountered were Campylobacter jejuni (21%), enteropathogenic Escherichia coli (EPEC) (18%), enterotoxigenic Escherichia coli (ETEC) (11%) and salmonella (8%). Of those cases having an identifiable cause 16% had more than one organism. The majority of children had mild disease and recovered clinically in 5.4 (1.3) days (Mean (s.d.]. The second study included 352 outpatients with diarrhoea who were randomly selected without regard to duration of disease or prior treatment. The results of faecal investigations were as follows: 28% had bacterial pathogens, 34% rotavirus, 15% parasites and 61% no pathogens. The bacteria most frequently detected were C. jejuni 7%, EPEC 7%, salmonella 6%, and shigella 5%. Ten per cent of positive cases had more than one pathogen. The most likely reason for the higher percentage with no identifiable pathogen is the prolonged duration of diarrhoea in 19% for more than seven days. In 128 control children with diarrhoea, stool samples were investigated during the same period as the two studies: 13% had bacteria, 2% rotavirus and 14% parasites. The bacteria involved were C. jejuni (5%). EPEC (5%), salmonella (2%) and shigella (2%).     

Enterotoxigenic Escherichia coli and other enteropathogens in paediatric diarrhoea in Addis Ababa

This study was performed during two weeks among 86 paediatric outpatients of poor socio-economic background. A control group comprised 60 healthy children. Enterotoxigenic Escherichia coli (ETEC) was the most common diarrhoeal agent isolated (26%). Strains of ETEC producing heat-labile (LT) only or LT and heat-stable (ST) enterotoxin were isolated from 11% each and ETEC producing ST only from 4% of the patients. ETEC was also found not infrequently among controls (10%). ETEC with O-antigens 78, 6 and 8 were shown to harbour colonization factors. Enterotoxigenic bacteria were found as contaminants in 5 of 24 feeding bottles investigated. Enteropathogenic Escherichia coli (EPEC) and Shigella species were isolated from 8% each and rotavirus from 24% of the patients. Twelve patients infected with ETEC only were compared to 66 patients not infected with ETEC. Patients infected with ETEC had a relatively mild disease and it was not possible by clinical findings to distinguish those patients infected with ETEC, LT and/or ST producing, carrying or not carrying colonization factors from those infected with other agents. This study underlines the need for extended studies of the clinical significance of ETEC infection in developing countries.     

Haemolytic uraemic syndromes in the British Isles, 1985-8: association with verocytotoxin producing Escherichia coli. Part 2: Microbiological aspects.

In a three year study of children under 16 years with haemolytic uraemic syndrome faecal samples were examined for the presence of Verocytotoxin producing Escherichia coli (VTEC) using DNA probes and for free neutralisable Verocytotoxin in a Vero cell assay with specific antisera. There was evidence of VTEC infection in 58 of 185 (31%) samples. A total of 53 VTEC was identified from patients with haemolytic uraemic syndrome. Thirty eight VTEC belonged to serotype O157:H7 or O157:H-, 34 produced VT2 only, and four strains produced both VT1 and VT2. The remaining 15 VTEC belonged to nine different O serogroups; three strains produced VT1, 10 produced VT2, and two were positive for VT1 and VT2. Three control groups of patients without haemolytic uraemic syndrome were also examined. There was evidence of VTEC infection in 8%, 6%, and 4% of specimens from individuals with bloody diarrhoea, those with diarrhoea only, and healthy controls respectively. VTEC from the bloody diarrhoeal and diarrhoeal controls were O157:H7 but those from the healty controls could not be O serogrouped. This study confirms the association of VTEC, and particularly strains of O157:H7, with haemolytic uraemic syndrome. Strains producing VT1, VT2, or both toxins were isolated, although over 94% of VTEC produced VT2 alone or together with VT1.     

Acute diarrhea in children less than 3 years of age: Enteropathogens isolated in patient's stools, compared with a control group

OBJECTIVES: To observe the occurrence of different etiological agents of acute diarrhea (AD) in stool specimens of patients and children in a control group. MATERIAL AND METHODS: 100 children less than three years of age with AD were studied as well as 100 controls, between November 1993 and May 1994. Stool specimens were collected in both groups and the following enteropathogens were searched for: Rotavirus, Escherichia coli (EPEC, ETEC, EIEC, EHEC), Salmonella sp, Shigella sp, Campylobacter jejuni, Campylobacter coli, Yersinia enterocolitica, Cryptosporidium sp, Giardia lamblia, Entamoeba histolytica. Statistical analysis using the exact Fisher test (at significance level p<0,05) was done. The mean age was 12,5 months, with more cases in patients less than 6 months (35%). Children were seen at the emergency section on an average fifth day after the start of the diarrhea. Most came from homes with basical sanitary conditions. Watery diarrhea was more frequent than bloody diarrhea with mucus, at a proportion of 4:1. RESULTS: Rotavirus was the most frequent agent: 21% in the AD group and 3% in the control group (p= 0,0001). Shigella sp was isolated in 7% of the AD group and none of the control group (p= 0,0140). EPEC was detected in 13% of AD cases and 7% in the control group (p= 0,2381) but the classical subgroups O55, O111, O119 were only isolated from the patients with AD. The other enteropathogens were infrequently detected or in equal proportion in both groups. Rotavirus and EPEC were the more frequently isolated agents in watery diarrhea, while Shigella sp was the predominant agent found in bloody stools with mucus. CONCLUSIONS: Rotavirus was the most common causative agent in AD. The detection of Rotavirus and Shigella sp nearly exclusively in patients with AD confirms the high patogenicity of these etiological agents when compared to the others. Escherichia coli (EPEC) diagnosed by polyvalent sera does not confirm its respective diarrheogenic property due to isolation in the same proportion among patients with AD and controls. Monovalent antisera made possible the detection of classical subgroups of EPEC O111, O119, O55 isolated only from AD patients, confirming the already known high patogenicity of these strains.     

ENTEROTOXIGENIC ESCHERICHIA COLI AND OTHER ENTEROPATHOGENS IN PAEDIATRIC DIARRHOEA IN ADDIS ABABA

ABSTRACT. This study was performed during two weeks among 86 paediatric outpatients of poor socio-economic background. A control group comprised 60 healthy children. Enterotoxigenic Escherichia coli (ETEC) was the most common diarrhoeal agent isolated (26%). Strains of ETEC producing heat-labile (LT) only or LT and heatstable (ST) enterotoxin were isolated from 11% each and ETEC producing ST only from 4% of the patients. ETEC was also found not infrequently among controls (10%). ETEC with O-antigens 78, 6 and 8 were shown to harbour colonization factors. Enterotoxigenic bacteria were found as contaminants in 5 of 24 feeding bottles investigated. Enteropathogenic Escherichia coli (EPEC) and Shigella species were isolated from 8% each and rotavirus from 24% of the patients. Twelve patients infected with ETEC only were compared to 66 patients not infected with ETEC. Patients infected with ETEC had a relatively mild desease and it was not possible by clinical findings to distinguish those patients infected with ETEC, LT and/or ST producing, carrying or not carrying colonization factors from those infected with other agents. This study underlines the need for extended studies of the clinical significance of ETEC infection in developing countries.     

Surveillance of hemolytic uremic syndrome in children less than 15 years of age, a system to monitor O157 and non-O157 Shiga toxin-producing Escherichia coli infections in France, 1996-2006

BACKGROUND: Since the 1980s, Shiga toxin-producing Escherichia coli (STEC), especially E. coli O157:H7, has been an important cause of food borne disease in industrial countries. In France, as there was no routine screening for STEC in clinical laboratories, enhanced surveillance of hemolytic uremic syndrome (HUS) in children less than 15 years of age was established in 1996 to monitor trends in the incidence of STEC infections. METHODS: The surveillance system was based on a voluntary national network of pediatricians of 31 pediatric nephrology units in public hospitals. RESULTS: From 1996 to 2006, the mean annual incidence of HUS was 0.71 cases per 100,000 children less than 15 years of age and 1.87 cases per 100,000 children less than 5 years of age. STEC infections were confirmed in 66% of patients; STEC O157 was the most common serogroup identified in STEC-related HUS (83%). In this 11-year period, 96% of HUS cases were sporadic and only 2 outbreaks caused by STEC O157 and by a dual infection of STEC O26 and O80 were detected. CONCLUSIONS: An evaluation of the surveillance of pediatric HUS showed that it is a simple and useful system for monitoring trends in STEC infections in France. It provides the information needed to measure the impact of new and changing vehicles of STEC transmission, and evaluate the effectiveness of prevention measures.     

Aeromonas spp associated with children's diarrhoea in Tehran: a case-control study

The study sought a possible pathogenic role for Aeromonas spp in Tehranian children presenting with diarrhoea. During a 10-month period (February to October 2001), 310 children <10 years of age with diarrhoea and a group of 310 age- and sex-matched controls were selected. Both groups were investigated for diarrhoeal pathogens. Of 310 children who presented with acute diarrhoea, Aeromonas spp was isolated from 14 (4.5%) (A. veronii biovar sobria 8, A. caviae 5 and A. hydrophila 1). The isolation rate was significantly higher than in the controls (p<0.001). Other enteropathogens were also more commonly isolated in children with diarrhoea: 57 (18.4%) Shigella spp (p<0.0001), 8 (2.6%) Salmonella spp (p<0.01), 7 (2.3%) enteropathogenic E. coli (p<0.05) and 8 (2.6%) Giardia lamblia (p<0.01). No enteropathogens were isolated in the control group. Dysentery was the dominant clinical feature in children positive for Aeromonas spp.